Production of terpineol



Feb. 10, 1953 J. E. SAPP ETAL 2,628,258

PRODUCTION OF TERPINEOL.

Original Filed Feb. 2, 1950 5 Sheets-Sheet 1 FIG. I.

TURPENTINE I! TREAT WITH H 30,, (60%) AND AsITnTE HT 070 5C. FOR SEVERHL V Houns MIXTURE OF HooI'TIoN PRooucrs Rm: Rom

DILUTE To 2.0 To50 H 80 WITH Cow WATER UNDER HeIT/ITIoN IN 20-50% ACID CENTRIFuoe SLURRY To FIEMovE DILUTE Rom tqND BY-PRODUCT OILs CRUDE TERPINOL HYDRHTE ls WAsHED Hm) NEuTR/ILIzED WITH SOLUTION OF NR2 C0 WnsH WITH WHTER To REMovE TFmcEs OF HLKnLI PHRTIH LLY PURIFIED TERPINOL HYpIanTE V BoIL IN 0.2M To 0.5M H 50 To PHRTIHLLY HYDROLIZE TERPINQI. HYDRFITE To CRUDE TERPINEOL HND SIMULTANEOUSLY STEBM DISTILL OFF THE OIL. CONTINUE UNTIL HLL TERPINEOL ls RECOVERED CRUDE TERPINEOL LVHGUUM FRAOTIONRTE INVENTORS. REFINED TERPINEoL END PRODUCT ff? THEIR AT ORNEYS.

Feb. W, 1953 J. E. SAPP ETAL 2,628,258

PRODUCTION OF TERPINEOL Original Filed Feb. 2, 1950 3 Sheets-Sheet 3 FIG. 3.

TURPENTINE TREAT UNDER HGITATION WITH 1.08

To 2.88 Pam-s OF 60% H 60 TO EnoH PART OF TURPENTINE FOR 1 2 T0 5HRs H1 5C. OR LowER, UNTIL MAXIMUM VISCOSITY OF MIXTURE ls REAcHED.

MIXTURE OF ADDITION PRooucTs AND Acm DILUTE SLOWLY INTO Soon Han SOLUTION IN Aaour 5O MmuTEs To PARTIALLY NEUTRALIZE To Lsnva 0.7N T 2.6M FREE Rom SLuRRY OF CRUDE TERPINOL HYDRATE 9ND BY-PRQDUCT OILS IN SLIGHTLY Acme SomuM SULFHTE SOLUTION V CRUDE TERPINEOL 2 VAcuuM FRAOTIONRTEI Bon. Hm: STEAM DISTILL SLURRY To FoRM AND RecovsR CRUDE TERPlNEOL REFINED TERPINEOL lgNvENToRs,

END PRODUCT .l

I v 7 PM & 'hca Patented Feb. 10, 1953 PRODUCTION OF TERPINEOL J unius E. Sapp and Wilbur F. Gillespie, Bogalusa,

and Paul A. McKim, Baton Rouge, La., assignors to Gaylord Container Corporation, St. Louis, Mo., a corporation of Maryland Continuation of application Serial No. 141,909, February 2, 1950. This application December 12, 1951, Serial No. 261,302 I 6 Claims.

This application is a continuation of our application, Serial No. 141,909, filed February 2, 1950, now abandoned.

This invention relates to the manufacture of terpineol from turpentine wherein the intermediate product, terpinol hydrate, is dehydrated to a predetermined controlled extent.

An oil of high terpineol content may be derived from partially refined or purified sulphate turpentine, gum spirits, steam distilled wood turpentine or other terpene hydrocarbons. Natural pine oil also contains terpineol as its chief constituent. Consequently, the product of this invention may be considered as a synthetic pine oil. It may be further purified to a highpurity terpineol by well known methods such as vacuum fractionation. 1

The principal object of this invention is to provide a simplified and more economical method of producing terpineol by introducing a turpentinea-cid mixture directly into an alkaline solution to form a slurry of crude terpinol hydrate in -:a salt solution within a controlled range of acidity whereby a high yield of oil of high terpineol content may be formed by boiling said slurry and recovering the oil by steam distillation.

Another object of the invention is to produce an oil of high terpineol content from terpinol hydrate.

Another object is to providea process for dehydrating terpinol hydrate by means of acid cat'- alysts in the presence of their salts.

A still further object is to provide means for employing a higher degree and wider range of acid concentrations in the partial dehydration of :2.

terpinol hydrate in the process of producing terpineol.

Other objects of the invention will be apparent from the description which follows and from the appended claims.

This invention relates to a process for producing terpineol from turpentine, said process comprising treating turpentine with an acid to form a mixture of crude terpinol hydrate, lay-products and acid, terminating the treatment approximately when the viscosity of said mixture reaches its maximum by partially neutralizing the mixture of acid and addition products :by introducing said mixture into an alkaline solution, the alkalinity of thesolution being controlled to provide an acidity of the resulting slurry just sufiicient to dehydrate the crude terpinol, dehydrating said terpinol by boiling said slurry and forming crude terpineol, and simultaneously recovering said crude terpineol by steam distillation.

The novel features of the invention may be conveniently shown by comparison of the following descriptions of the conventional process and of the process of this invention.

' In the accompanying drawings which form a part of this specification:

Fig. 1 is a flow sheet for a conventional process for producing terpineol from turpentine,

Fig. 2 is a graph showing the yield of terpineol as against the normality of sulphuric acid in spent liquor at various Na2SO4 concentrations, v

and

Fig. 3 is a flow sheet for this new process for producing terpineol from turpentine.

A typical conventional process for producing terpineol comprises a series of time and labor consuming steps illustrated by the flow sheet shown in Fig. 1.

The first step of the conventional process consists in treating the turpentine with acid, for example, sulfuric acid of a concentration of about 60% at a temperature in the range of 0-5 C. for several hours to form an addition compound which dissolves in the acid.

The 2d step consists in diluting this mixture by introducing it into a sufiicient quantity of cold water to reduce the acid concentration to about 20% 3(l% H2804. The mixture is agitated during dilution, the acid-turpentine addition product quickly hydrolyzing to form a slurry of crude terpinol hydrate and oily by-products in the dilute acid.

An alternate method of carrying out the 1st and 2d steps described is to treat the turpentine under agitation with more dilute acid, for example, 25% sulfuric acid for several days. In this case the addition compound is presumably formed and slowly hydrolyzed forming terpinol hydrate and oily by-produ-cts in one step but at the expense of vastly increased time of reaction.

In the 3d step, the crude terpinol hydrate is removed from the dilute acid by centrifuging, along with'a considerable portion of the oily byproducts.

In the 4th step the damp centrifuged terpinol hydrate, still containing'some acid, is neutralized with a solution of an alkali'suc'h as sodium carbonate to remove the residual acidity.

In the 5th step the terpinol hydrate is thoroughly washed withvwater. The terpinol hydrate is now in a partially purified state but still contains small quantities of the by-product oils, and unless the washing has been extremely thorough, will still contain traces of the alkali.

In the 6th step the partially purified terpinol hydrate is partially dehydrated by boiling in the presence of a dilute acid catalyst such as H2804 of a concentration in the range of about 0.2 N to 0.5 N, forming crude terpineol, which i simultaneously removed from the reaction vessel by steam distillation.

The oil thus obtained is of a fair degree of purity, having for example, a terpineol content.

of 85% to 90%, and a yield of 50% to 55%- by. weight on the weight of the turpentine treated. The actual terpineol content: is about 421% to 49 by weight based on the weight of the turpentine.

The by-product oil removed from the slurry of crude terpinol hydrate by centrifuging in the third step of the process, contains appreciable quantities of turpineol. Since this by-product oil may constitute 30% to 35% by weight of the turpentine treated and contains some terpineol, an addition to the yield of terpineol may be obtained by separately treating it, though at a consider- .able added operating expense".

To obtain this additional yield", the by-product oil is steam distilled to separate the nonvolatile v polymers and remove traces of acid. The volatile fraction of the by-product onmay amount to about by weight of the turpentine. and contain to- 32% of actual terpineol, so that 7.5% to 8% additional terpineol may be recovered by this additional step.

This oil may then be fractionated to. obtain an oil of higher terpineol content, if so desired- Thus the best overall yield of crude terpineol comprising the direct recovery plus the returns from steam distilling the by-product oil that may be expected from the conventional process amounts to about 75% to 80% by weight based on the turpentine, and the yield of actualterpineol is about 49% to 56% by" weight based. on the turpentine.

Among the disadvantages of a typical. conventional process are the following:

1. It involves a multiplicity of steps including a relatively high laborand. processingv cost.

2. A difficult operating problem consists in. the

disposal of the dilute acid centrifuged; from the completely dehydrate the terpinol hydratev and form undesirable hydrocarbons. By reference: to curve A of Fig. 2; the efi'ect of very'small variations in the acidity of the slurry on theyield of terpineol is evident. For;example; at 0 .2 N H2504, the terpineol content: is about 12.5%: while at 0.4 N'it' falls to aboutr58 andlabove that acidity, falls rapidly to still lower percentages. In practice, therefore, the. acidity must be controlled within quite low limits in order to obtain an oil of even fair quality.

This critical control of the acidity imposes a diflicult operating problem. requiring a. high degree of skill, care and vigilance. Furthermore, the crude terpinol hydrate may be contaminated 4 with unknown quantities of acid or alkali so that a further difiiculty arises in accurately adjusting the acidity of the very dilute treating solution initially.

One way of increasing the yield of' terpineol is to use the conventional process shown in Fig. 1 and hereinbefore described up to the point of dehydration, and then add a salt of an acid catalyst..

The conversion of terpinol hydrate to terpineol involves the removal of one of the two tertiary hydroxyl groups from the terpinol hydrate molecule to form an ethylenic linkage. This may be accomplished by boiling the terpinol hydrate in dilute solutions of mineral acids, organic acids, certain salts, etc..

The usual. commercial method of effecting the conversion as hereinbefore described is to treat the terpinol hydrate at atmospheric boiling temperature with dilute sulfuric or phosphoric acid. Generally, unless'th'e' concentration of acids is accurately controlled initially and throughout the dehydration cycle to relatively low concentrations, the reactionv proceeds with great rapidity, is dimcult to control and results in an oil containing a. relatively low percentage of terpineol contaminated with excessive quantities of. terpene hydrocarbons.

For example, when: sulfuric acid is used as a dehydrating agent, th acid concentration must not exceed approximately 0.5 N to avoid excessive and undesirable dehydration of the terpinol hydrate. On the other hand, as the. concentration is reduced it becomes increasingly difficult to accurately control and the rate or reaction is progressively reduced and finally proceeds so slowly as to be commercially impractical- Thus to obtaineven fair yields of terpineol, the industry is faced with the extremely difficult practical problem of accurately controlling the HzSOe concentration within low, narrow limits, not in any event exceeding about 0.5 N.

By reference to Fig. 2', the significance of control of the concentrations of" acids on the purity of terpineol is illustrated. by the steep character of curve A. For example, at 0.1 N, the purity of the oil is about? 81% at 0.2'N, about 72%,. while at. 0.4. N it falls to; 58% or 159%. Above the higher concentration it will be observed that the purity falls 'oif so .rapidly' as to" prohibit the use of higher concentrations;

Following is: an example. of the conventional V EXAMPLE I 150 grams of chemically pure terpinol hydrate were boiled with 1000 milliliters of 0.405 N suliuric acid, theoil was continuously removed from the reaction mixtureby steamv distillation. 115 grams of product were obtained having an actual terpineol content of. 59.0%.. The yield of crude terpineolv by weight was. 76 of the weight of the terpinol hydrate, while the yield by weight of actual terpineol based on the weight of the terpinol hydrate was 45%.

We have discovered that the extremely high reactivity of: acidcatalysts in the dehydration process may be substantially inhibited. and a considerably higher. and wider range of acid concentrations employed by carrying out thereaction in the. presence of salts of the. acids employed. For example, with the use of a sodium sulphate solution, a sulfuric acid concentration of 1.5 N- will result in an oil containing about 85% terpineol. By reference to curve B of Fig. 2 it will be seen -that"the presence of sodium sulphate gives oils.

of terpineol content of 80% to as high as 96 %v to 97%. Such higher acid concentrations are far easier to control and furthermore with the use of the salts of the acids, no such extremely accurate adjustment of acidity i required such as is typical of the conventional processes.

Our discovery therefore permits the production of terpineol of much more highly refined quality than is obtainable with the conventional processes.

The following examples illustrate the improvement in yield and quality of terpineol resulting from the use of various acid catalyst in the presence of a salt of the acid employed, or salts other than the salt of the acid employed.

EXAMPLE 2 150 grams of chemically pure terpinol hydrate were boiled with 1000 milliliters of 1.04 N sulfuric acid in which 250 grams of sodium sulphate were dissolved. The terpineol was continuously removed from the reaction mixtur by steam distillation. 121 grams of product were obtained which contained 92.8% actual terpineol.

The yield of crude terpineol by weight was 81% of the weight of the terpinol hydrate, while the yield by weight of actual terpineol based on the weight of the terpinol hydrate was 75 EXAMPLE 3 50 grams of terpinol hydrate were boiled with 1000 milliliters of 0.57 N phosphoric acid containing 263 grams of salt-cake. (95% Na2SO4.) The oil formed was continuously removed by steam distillation. The yield of oil was 40 grams, analyzing 98% terpineol.

The yield of crude terpineol was 80% by weight and. the yield of actual terpineol 78.4% .based on the weight of the terpinol hydrate.

EXAMPLE 4 50 grams of terpinol hydrate were boiled with 1000 milliliters of 1.10 N phosphoric acid containing .263 grams of saltcake. (95% NazSO4.) The oil formed was continuously removed by steam distillation, the yield being 40 grams analyzing 97% terpineol.

The yield of crude terpineol by weight was 80% and the yield of actual terpineol 77.6% based on the weight of the terpinol hydrate.

EXAIVIPLE 5 50 grams of terpinol hydrate were boiled in 1000 milliliters of 0.50 N oxalic acid. The oil formed was removed by steam distillation and the yield was 39 grams analyzing 70% terpineol.

The yield of crude terpineol by weight was 78% and of actual terpineol 54.6% based on the weight of the terpinol hydrate.

EXAMPLE 6 50 grams of terpinol hydrate were boiled with 1000 milliliters of 2.01 N oxalic acid containing 158 grams of ammonium oxalate. The oil formed was removed continuously by steam distillation and the yield was 40 grams analyzing 80% terpineol.

' NaOH, KOH, K2003, etc.

with 0.4 N (see curve A, Fig. 2).

'6 was continuously removed by steam distillation and the yield was 40 grams analyzing 87% terpineol. i

The yield of crude terpineol by weight was 80 and the yield of actual terpineol 68.4% based on the weight of the terpinol hydrate.

The new process of this invention imposes no such difiicult control problem with respect to acidity in the dehydration step, eliminates several entire steps of the hereinbefore described conventional process and in addition, avoids the losses in yields and the troublesome acid recovery or disposal problem.

This improvement is accomplished by diluting the mixture of turpentine-acid addition product by feeding it directly into a soltuion of an alkali whereby a salt solution is formed and the acid concentration is reduced to a range such that upon boiling, terpineol of good quality is produced in a high yield.

The alkaline solution may be prepared with soda ash, for example, so that upon introducing the mixture of turpentine-acid, the sodium salt is formed; it may also be prepared with ammonia, Other acids may also be used in the process, for example, phosphoric acid but sulfuric acid is prefered on account of its low cost.

By referring to curve B of Fig. 2, it will be seen that with an aqueous solution of sodium sulphate containing 380 grams of NazsOi per liter and about 2.0 N with respect to sulfuric acid, the purity of the crude terpineol from terpinol hydrate is about 79% while at an acidity of 0.9 N it rises to 93-94%. Even at a concentration of 2.4 N the purity is 71% or far greater than that which is obtained by the conventional process Thus the range of acidity in which a high quality terpineol can be produced is greatly extended when the dehydration is carried out in the presence of salts such as sodium sulphate, and a higher acid concentration may be employed than in the conthis process are as follows:

The yield of crude terpineol by weight was and the yield of actual terpineol 74.4%

1000 mililiters of 2.02 N oxalic acid containing 250 grams of potassium sulfate. The oil formed A. The highest yields of terpinol hydrate and correspondingly of terpineol, are obtained at "weight ratios of sulfuric acid (basis to turpentine in the range of 1.08: 1 to 1.80:1.

Higher ratios up to 2.88:1 have been used but without any significant improvement in yield than with ratios in the preferred range. Lower ratios result in lower yields of terpinol hydrate and while the chemical costs are correspondingly lower, in general they are offset by the lower yield of the desired product.

. B. Insofar as the yields of terpinol hydrate are concerned, it makes little difference whether .the turpentine is added to the acid or vice versa. '.We prefer to add the turpentine to the acid because the mixture of the two liquid phases is more readily accomplished in this manner and,

furthermore, the highest yields of terpinol hydrate are obtained in a shorter time.

0. The time of addingthe turpentine to the acid is important only in that it should be held within such limits as to avoid a rise in temperature above about 5 C. The time of addition of the acids is a function. of the-refrigeration capacity available. Ordinarily the addition can be completed under satisfactory temperature conditions in from 30-to 45 minutes. If the temperature of the mixture is allowed to exceed about C. the reaction rate is accelerated but the yield is decreased. At temperatures below 0 C. the reaction rat is slowed without any appreciable increase in yield over that obtained within the preferred range of temperature control.

D. Acid concentrations between 55% and 65% may be employed but we prefer to operate within the range of 57% to 62%. At higher concentrations the reaction is faster, the temperature more diflicult to control and the yields are lower. At lower acid concentrations the rate of reaction is slower while the yields are not improved- E. As the reaction between the turpentine and the acid proceeds, the yield of terpinol hydrate increases to a maximum value and then slowly declines. Thus for best results it is desirable to terminate the reaction at, or near, the point of maximum .yield. A convenient means for determining the maximum yield point is the viscosity of the reaction mixture. We have found the viscosity to be a reliable index of the progress of the eraction and that the maximum viscosity coincides with the maximum yields of terpinol hydrate. Since the speed of reaction is dependenton the acid concentration and the temperature within the preferred ranges set forth above, th highest yield may be obtained over a considerable variation of the reaction time, usually within 1 /2 to 3 hours.

The second step in the process comprises the novel method of diluting the mixture of acid and turpentine addition product formed by the treatment of turpentine and acid described in the first step. A solution of an alkali, preferably soda ash, is formed into which the turpentine-acid -;-1

mixture is added. The solution contains a sumcient amount of soda ash to partially neutralize theresulting mixture and form a slurry of crude terpinol hydrate suspended in a slightly acidic solution of the sodium salt (sodium sulphate when sulfuric acid is used). Solutions of other alkalis may he used, if desired, to form salts of the acid catalyst employed.

, The turpentine-acid mixture should be added tothe alkali solution rather than vice versa. In this manner the acidity is reduced to a low value so quickly that there is no undesirable effect on the yield of terpinol hydrate. However, since a considerable amount of carbon dioxide, as well as heat is evolved when the turpentine-acid mixture is partially neutralized by the alkali, care must be taken not to carry out the neutralization too rapidly in order to avoid the tendency to boil out the contents of the vessel by too rapid an evolution of carbon dioxide andto preventoverheating the entire mass with consequent formation of hydrocarbons and polymers. It has been found that the addition may be conveniently and advantageously carried out in from to 45 minutes, preferably about 30 minutes.

The quantity of alkali used to partially neutralize the turpentine-acid reactionmixture depends primarily upon the ratio of acid-turpentine used in the first step of the process. The objective is to produce a salt solution, for example, sodium sulphate solution, having suiiicient acidity to dehydrate the terpinol hydrate to just the re quired extent to form crude terpineol and avoid excessive, dehydration with resulting undesirable terpene hydrocarbons and lower yields of terpineol.

' "We have found that in the presence of concentrated sodium sulphate solution, sulfuric acid concentrations within the range of 0.7 N to 1.6 N are very satisfactory and pr du the highest yield of crude terpineol with a minimum quantity of undesirable terpene hydrocarbons. However, concentrations below 0.7 N and above 1.6 N may be'used and yield satisfactory results without the difiicult problem of control of concentrations ofthe lower values within very narrow limits inherent in the conventional process on the one hand, or encountering undue or prohibitive decrease in terpineol purity on the other. In fact, concentrations from approximately 0.7 N to 2.6 N may be used. 7

, In the reaction of this step of the process, sodium sulphate is formedas a by-product when H2804 is used as a' catalyst and soda ash as an alkali. 'Since this material has a wide market for many purposes, including the kraft pulping process from which one of the starting materials [or manufacturing terpineol is derived, namely, sulphate turpentine, it is desirable to end the second step'of the process with as concentrated a solution of sodium sulphate as possible in order to minimize the evaporation required to recover the sodium sulphate. Consequently the alkaline solution to which the turpentine-acid mixture is added is formed with a minimum quantity of water so as to produce a highly concentrated sodium sulphate end solution. We have found that good results ar obtained with a water to soda ash ratio from 2:1. to 1:1. Higher ratios of water may be used but it is uneconomical and in addition, as the sodium sulphate solution is diluted a loweracidity must be used to obtain the same degree ofpurity. of terpineol.

Upon completion of the addition of the reaction mixture to the alkaline solution the slurry is heated to boiling temperature by means of a closed steam coil in the dehydrator whereby the terpinol hydrate is converted to terpineol. The terpineolis removed from the reaction zone by simultaneous introduction of live steam by means of a'perforated steam coil, the vapor condensed and the oil and water layers separated by decantation. A preferred example of the process is described as follows:

50 pounds of refined sulphate turpentine were reacted with 57% H2S04 in a molar ratio of 2:1 at 0-5 -C.- for 2% hours.

The resultant mixture was slowly poured into a solution containing 71 pounds of soda ash and 41 poundscfwater. This produced a terpinol hydrate slurry in a, concentrated aqueous solution of sodium'sulphate with an amount of free acid to result in a concentration of 0.72 N.

Upon boiling the solution and removing the crude oil by steam distillation 45.4 pounds of crude terpineol were obtained, which analyzed 74.4% actual terpineol.

The yield of crude terpineol was 91%, by weight, based on the weight of the turpentine treated, or 67.6%, by weight, of actual terpineol on the weight of the turpentine treated.

This yield of crude terpineol of 91% by the process of this invention using 0.72 N concentration of acid in the dehydration step compares with 50% to 55% by the hereinbefore described conventional. process. Even when the expemive additional conventional step of recovering the terpineol from the by-product oils is employed,

9. the best total yield of volatile oils by the conventional process is only about 75% to 80% by weight. I based on the weight of the turpentine. I

Following is a comparison of yields and degrees cf refinement of terpineol by the usual and new '5 processes:

Comparison of terpineol yields [By weight on weight of turpentine] d hum. -nflnmv... -7. A.. .n ..v Conveui tional P iii ss I Process Percent Crude Terpineol by Direct Steam Dlstillatiom. 50-55 91%. Terplueol Content of Crude Yield 85-90 74. 4%. Percent Actual 'lerpineol on Turpentine -i249 68%.- 7 Steam Volatile By-Product OiL... 25 Percent actual Terpineol in Steam Volatile By-Product Oil 7-8 Total Steam Volatile Oil Produced 75-80 9l%. 'lotal Percent Actual Terpineoi Yield. on

'Iurpentine 49-07 b8%.

The new process does not involve the steam distiliation of two separate oil fractions as described in the conventional process but achieves a direct one step yield of crude oil of good quality consid erably greater than realized from the corresponding step of the conventional process. The actual terpineol content of the partially refined product is 20% to greater than from the usual process.

Even including the terpineol which may be recovered by the time consuming and costly addia tional steam distillation of the by-product oils by the usual process, the actual terpineol content of the oil by the new process is 10% to 20% greater by weight based on the weight of the turpentine.

In addition to the much improved yields of partially refined oil, the new process, comprising essentially but three steps in contrast to at least six separate steps by the usual process (seven including recovery of the terpineol from the byproduct oils), is simpler, and results in important economies in time, labor and materials.

Following is an example of the use of phosphoric acid in the process of this invention:

270 grams of refined sulphate turpentine were reacted with 460 grams of 85% phosphoric acidat 0-5 C. for 2 /2 hours.

The resulting turpentine-acid mixture was slowly introduced into 1000 milliliters of an ammonium hydroxide solution containing 130 grams of ammonium hydroxide. The resulting slurry of terpinol hydrate contained sufficient free phosphoric acid to give an acid concentration of approximately 5 N.

The slurry was boiled and the crude terpineol removed by steam distillation. Small increments of phosphoric acid were added during the distillation to increase the rate of formation of terpineol so that the final acid concentration was about 8.0 N and the final ammonium phosphate concentration approximately 125 grams per liter.

231 grams of crude terpineol were obtained, representing a yield of 85.5% by weight based on the weight of the turpentine.

The terpineol content of the crude was or about 60% by weight on the weight of the turpentine.

Other concentrations of phosphoric acid may be employed as desired without departing from the scope of the invention.

As shown in this example, salts of the acid 10 catalysts employed other than sodium salts may be used if desired, though from the standpoint of economy it is usually preferred to form the alkaline solution with the use of soda ash.

Mixtures of sulphuric and phosphoric acids, as well as other acid catalysts may be used to excellent advantage, but as heretofore mentioned, We prefer to use sulphuric acid because of its relatively low cost.

The invention thus provides an economical process of a much reduced cycle of operations for producing greatly increased yields of partially refined terpineol from turpentine which may be further refined to any desired degree of purity by the well known vacuum fractionating processes.

Since certain obvious changes may be made in the details of the above procedures, in the acid catalysts employed and in the composition of the alkaline solution into which the turpentine-acid mixture is introduced without departing from the scope of the invention, it is intended that all the matter contained in the above description shall be interpreted as illustrative of the invention and not as a limitation thereto.

What We claim is:

1. The process of producing terpineol from turpentine comprising mixing turpentine in the weight ratio of one part thereof with about 1.08 to 2.88 parts of sulphuric acid bases of percent at a concentration of about 60 percent and at a temperature of 0 to 5 C. to form a reaction therebetween, said reaction continuously producing crude terpinol hydrate dissolved in the acid mixture gradually up to maximum viscosity, introducing the mixture at its maximum viscosity directly into an alkali solution thus forming a slurry consisting of a free acid, terpinol hydrate and a. concenerated aqueous salt solution, the free acid in the slurry being of the range of from approximately 0.7 N to 2.6 N, boiling the slurry to dehydrate the terpinol hydrate and form crude terpineol, and recovering the crude terpineol from the slurry.

2. The process as defined in and by claim 1 wherein the alkaline solution is formed from soda ash, and the concentrated aqueous solution is sodium sulphate.

3. The process of producing terpineol from turpentine comprising mixing turpentine in the weight ratio of one part thereof with about 1.08 to 2.88 parts of sulphuric acid basis of 100 percent at a concentration of about 55 to 65 per cent, at a temperature of 0 to 5 C. and Within about 1 hours to 3 hours to form a reaction therebetween, said reaction continuously producing crude terpinol hydrate dissolved in the acid mixture gradually up to maximum viscosity, introducing the mixture at its maximum viscosity directly into an alkali solution thus forming a slurry consisting of a free acid, terpinol hydrate and a concentrated aqueous salt solution, the free acid in the slurry being of the range of from approximately 0.7 N to 2.6 N, boiling the slurry to dehydrate the terpinol hydrate and form crude terpineol, and recovering the crude terpineol from the slurry.

4. The process as defined in and by claim 3 wherein the alkaline solution is formed from soda ash, and the concentrated aqueous solution is sodium sulphate.

5. The process of producing terpineol from turpentine comprising mixing turpentine in the weight ratio of one part thereof with about 1.08 to 2.88 parts of sulphuric acid basis of 100 percent at a concentration of about 60 per cent, at a temper- 131 ature of 0 to 5C. and within about 1 to 3 hours to form a reaction therebetween, said reaction continuously producing crude terpinol hydrate dissolved in the acid mixture gradually up to maximum viscosity, introducing the mixture gradually within a period of about 40 to 45 minutes, at its maximum viscosity directly into an alkali solution thusforming a slurry consisting of a free acid, terpinol hydrate and a concentrated aqueous salt solution, the free acid in the slurry being of the In range of from approximately 0.7 N to 2.6 N, boiling the slurry to dehydrate the terpinol hydrate and form crude terpineol, and recovering the crude terpineol from the slurry.

6. The process as defined in and by claim 5 15 12 wherein the alkaline solution is formed fromsoda ash, and the concentrated aqueous solution is sodium sulphate.

JUNIUS E. SAPP. WILBUR F. GILLESPIE. PAUL A. McKIM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,052,743 Bibb Sept. 1, 1936 2,088,030 Mevly July 2'1, 1937 2,432,556 Borglin Dec. 16, 1947 

3. THE PROCESS OF PRODUCING TERPINEOL FROM TURPENTINE COMPRISING MIXING TURPENTINE IN THE WEIGHT RATIO OF ONE PART THEREOF WITH ABOUT 1.08 TO 2.88 PARTS OF SULPHURIC ACID BASIS OF 100 PERCENT AT A CONCENTRATION OF ABOUT 55 TO 65 PER CENT, AT A TEMPERATURE OF 0* TO 5* C. AND WITHIN ABOUT 11/2 HOURS TO 3 HOURS TO FORM A REACTION THEREBETWEEN, SAID REACTION CONTINOUSLY PRODUCING CRUDE TERPINOL HYDRATE DISSOLVED IN THE ACID MIXTURE 